High CO - at High RPM

This condition is indicated by abnormally high carbon monoxide with low or normal hydrocarbon emissions during cruise (2500 rpm).


POSSIBLE CAUSE


PCV Malfunction
- Check PCV system in "Testing Procedures"

Restricted Exhaust
- Check Catalytic Converter in "Testing Procedures"

Incorrect Spark Advance
- Check Ignition Timing in "Adjustment Procedures"

Verify Vehicle Remains in Closed Loop at Steady Throttle (2500 rpm) and Oxygen Sensor is Working
- Test the Fuel Injection System. Refer to "On-Board Diagnostics" for models so equipped

Fuel Injected Fuel Metering Malfunction
- Check fuel pressure
- Perform injector balance test
- Service Fuel Injectors (Pressure cleaner)